Sustainable bacteria-based self-healing fiber reinforced concrete

Self-healing concrete presents an innovative and eco-friendly solution with the potential to reduce maintenance costs through self-activated crack repair. This study examined the effect of varying bacterial content across different environmental conditions. Additionally, the coupling effect between bacteria and steel fiber to enhance the mechanical and physical properties at different ages has been investigated. Bacillus Sphaericus (B. Sphaericus) was incorporated into the concrete at concentrations of 2 x 109 (CFU/ml), and different bacterial percentages selected utilizing calcium lactate as a nutrient source. Bacterial content of 0.0 percent, 0.25 percent, 1.0 percent, and 2.5 percent, cured in both fresh water and magnesium sulfate water solution, were tested to examine concrete behavior in harsh environments. Additionally, steel fibers at volume fraction percentages (Vf percent) of 1.0 percent and 1.5 percent, along with 1.0 percent bacterial content, were tested to highlight their combined effect. Tests were conducted at different ages to measure compressive, tensile, and flexural strengths. In addition, SEM and EDS analyses for cracked and uncracked specimens were performed. The results showed a significant increase in the long-term compressive, tensile, and flexural strengths at 180 days by 47 percent, 80 percent, and 50 percent, respectively, with a bacterial content of 2.5 percent. Moreover, the incorporation of steel fibers, 1.0 percent and 1.5 percent content, in the bacterial concrete resulted in a long-term compressive strength increase at 180 days by 45 percent and 55 percent, respectively with 1.0 percent bacterial content, compared to 15 percent and 27 percent for 0 percent bacteria. Curing in sulfate-rich water, concrete specimens exhibited increasing compressive strength at 180 days from 47 MPa for 0 percent bacteria to 77 MPa with 2.5 percent bacteria content. Despite lower initial strength of 29 MPa at 7 days, bacterial incorporation led to significant strength improvements, highlighting effective self-healing even in aggressive curing environments.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Civil engineering (MU)

Grantor dc:publisher

University of Missouri--Columbia

Year dc:date.issued

2024

Author dc:creator

• Helal, Zinab Abdalla

Advisor dc:contributor.advisor

• Salim, Hani

Language dc:language.iso

eng, English

DOI

https://doi.org/10.32469/10355/104987

OAI identifier oai:identifier

oai:mospace.umsystem.edu:10355/104987